Change short help messages to imperative voice

Unify the output of `restic help`.

cmd/restic/cmd_forget.go

@@ -13,7 +13,7 @@ import (
 
 var cmdForget = &cobra.Command{
 	Use:   "forget [flags] [snapshot ID] [...]",
-	Short: "forget removes snapshots from the repository",
+	Short: "remove snapshots from the repository",
 	Long: `
 The "forget" command removes snapshots according to a policy. Please note that
 this command really only deletes the snapshot object in the repository, which

cmd/restic/cmd_tag.go

@@ -13,7 +13,7 @@ import (
 
 var cmdTag = &cobra.Command{
 	Use:   "tag [flags] [snapshot-ID ...]",
-	Short: "modifies tags on snapshots",
+	Short: "modify tags on snapshots",
 	Long: `
 The "tag" command allows you to modify tags on exiting snapshots.
 

doc/man/restic-forget.1

@@ -5,7 +5,7 @@
 
 .SH NAME
 .PP
-restic\-forget \- forget removes snapshots from the repository
+restic\-forget \- remove snapshots from the repository
 
 
 .SH SYNOPSIS

doc/man/restic-tag.1

@@ -5,7 +5,7 @@
 
 .SH NAME
 .PP
-restic\-tag \- modifies tags on snapshots
+restic\-tag \- modify tags on snapshots
 
 
 .SH SYNOPSIS

doc/manual.rst

@@ -21,7 +21,7 @@ Usage help is available:
       cat           print internal objects to stdout
       check         check the repository for errors
       find          find a file or directory
-      forget        forget removes snapshots from the repository
+      forget        remove snapshots from the repository
       init          initialize a new repository
       key           manage keys (passwords)
       list          list items in the repository
@@ -31,7 +31,7 @@ Usage help is available:
       rebuild-index build a new index file
       restore       extract the data from a snapshot
       snapshots     list all snapshots
-      tag           modifies tags on snapshots
+      tag           modify tags on snapshots
       unlock        remove locks other processes created
       version       Print version information